The present invention relates a light-emitting device for use in various apparatuses such as image-taking apparatuses including a digital still camera and a video camera, and camera-equipped cellular phones.
Some of image-taking apparatuses such as a video camera and a digital still camera have a capability to take an image of an object (or subject) at an extremely close range from an image-taking lens (a macro photography capability).
In such macro photography, the use of a typical illumination apparatus (a light-emitting device) provided for a camera, for example at an upper portion thereof, causes disadvantages such as a failure to illuminate uniformly a necessary irradiation area resulting from part of the illumination light being blocked by a lens barrel, and an unnatural image including a dark shadow on one side of an object.
Thus, an illumination apparatus has been proposed in which a ring-shaped light emergence portion or a plurality of light emergence portions are disposed around the end of a lens barrel to allow illumination suitable for the macro photography (see Japanese Patent Laid-Open No. 2004-23412 or Japanese Patent Laid-Open No. 2000-314908).
Japanese Patent Laid-Open No. 2004-23412 has proposed an illumination apparatus in which light emitting from a flash unit for normal image-taking is directed to the periphery of a lens barrel by using a number of optical fibers. Japanese Patent Laid-Open No. 2000-314908 has proposed an external illumination apparatus which has a ring-shaped portion which is disposed on the outer periphery of a lens barrel to direct illumination light from a light source in the circumferential direction of the ring-shaped portion before emergence.
In recent years, small apparatuses including a camera-equipped cellular phone often employ a light-emitting device which is used as a substitute for a flashlight and performs display by lighting or blinking of light or changing colors of light as a means for showing a user the status of the apparatus as well as having the function of illuminating an object.
Japanese Patent Laid-Open No. 2001-255574 has made a proposal in which a light-emitting device formed of a plurality of LEDs is disposed around an image-taking lens contained in a cellular phone such that the light-emitting device illuminates an object in taking an image and the light-emitting device is blinked in response to an incoming call on the cellular phone.
In the illumination apparatus proposed in Japanese Patent Laid-Open No. 2004-23412, however, the use of a number of generally expensive optical fibers increases the cost of the illumination apparatus or the like, or no optical member provided for controlling light emerging from the optical fibers makes it impossible to achieve a desired light distribution characteristic.
In the illumination apparatus proposed in Japanese Patent Laid-Open No. 2000-314908, considering the way of directing luminous flux from the light source to the ring-shaped portion and the shape of the ring-shaped portion described in an embodiment thereof, it is likely that the efficiency of use of the light from the light source is reduced or a desired light distribution characteristic is not realized in reality.
On the other hand, in the cellular phone proposed in Japanese Patent Laid-Open NO. 2001-255574, a plurality of light sources are provided but the luminous fluxes therefrom do not emerge through a single (common) optical system. In other words, an optical system is provided for each of the light sources, so that a number of parts are required for illumination and display to need large space and the resulting cellular phone is inevitably expensive.